Various workpieces are provided with a surface coating in order to protect their surface and/or to superpose particular properties. In addition to forming a coating that is as homogeneous as possible, a proper functioning of this protective coating requires that it bonds well to the workpiece to be coated. If this is not the case, then the intended protective effect can be in part considerably impaired or disturbed. Other disturbing factors may be due to damage to the surface of the workpiece to be coated and/or to irregularities in the protective coating to be applied.
Such disturbances or flaws in the coating may be e.g. blistering, craters, popping, dirt, wetting disturbances, spreading disturbances or the like.
For the purpose of inspecting coatings, visual assessments of the coated surfaces are possible and known, in part using appropriate technical aides such as the use of a microscope or the like. Automating the detection of flaws with the aid of a camera and an image evaluation is in part massively impeded by exposure and/or reflection problems with respect to the different reflective properties of different coating materials or even of the colors of similar coating materials. Thus, for example, an automatic coating inspection of clear lacquers, black-pigmented lacquers and very highly glossy lacquers is not possible due to an insufficient level of contrast.